A quasar's identity may simply be in eye of beholder

A quasar is a super-massive black hole; quasars are among the most energetic objects in the Universe. Most quasars are extremely bright in optical light, but about 10 percent of them appear hidden by clouds of gas and dust. Are these 10 percent different from the rest of the quasars? Astronomers have debated whether these shrouded quasars represent an early evolutionary stage of black holes when they vigorously consume matter, or whether these energetic outflows are present in all quasars, but detectable only when viewed in certain orientations. Recent observations of 10 quasars made by a research team led by a researcher from the Harvard-Smithsonian Center for Astrophysics shows that it's the angle of observation that makes some quasars appear shrouded. The observations were made using NASA's Chandra X-ray Observatory. NASA's Marshall Space Flight Center, Huntsville, AL, manages the Chandra program for the Office of Space Science, Washington, D.C. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, MA.